Draw lines along the grid edges to divide the grid into connected regions, so that every region contains exactly one of each letter. Every letter appears the same number of times in the grid, so the regions all come out the same size: a 6×6 grid using four letters divides into nine four-square regions, each holding one A, one B, one C and one D.
Click on a grid edge to mark it as a division between regions (black), and again to return to marking it as undecided (yellow). Right-click on a grid edge to mark it as definitely not a division (faint gray), and again to mark it as undecided again. The arrow keys move a cursor over the edges of the grid; Enter marks the edge as a division, and Space marks it as definitely not one.
A region is shaded once it is complete and correct. Lines that close off a region of the wrong size are shown in red, as is a letter that appears twice within one region.
Use the Type menu to change the size of the grid and how many different letters it uses.